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@ecatmur ecatmur commented Jan 14, 2023

https://sourceware.org/bugzilla/show_bug.cgi?id=17272

linked: ecatmur/gcc#5

Command line to send patch:

git send-email -1 --to gdb-patches@sourceware.org --subject-prefix "PATCH v2][PR 17272"

@ecatmur ecatmur marked this pull request as draft January 14, 2023 13:31
@ecatmur ecatmur force-pushed the bug-17272 branch 4 times, most recently from fdd5065 to bc12da6 Compare January 15, 2023 22:40
ecatmur pushed a commit that referenced this pull request Feb 4, 2023
I would like to improve frame_info_ptr to automatically grab the
information needed to reinflate a frame, and automatically reinflate it
as needed.  One thing that is in the way is the fact that some frames
can be created out of thin air by the create_new_frame function.  These
frames are not the fruit of unwinding from the target's current frame.
These frames are created by the "select-frame view" command.

These frames are not correctly handled by the frame save/restore
functions, save_selected_frame, restore_selected_frame and
lookup_selected_frame.  This can be observed here, using the test
included in this patch:

    $ ./gdb --data-directory=data-directory -nx -q testsuite/outputs/gdb.base/frame-view/frame-view
    Reading symbols from testsuite/outputs/gdb.base/frame-view/frame-view...
    (gdb) break thread_func
    Breakpoint 1 at 0x11a2: file /home/simark/src/binutils-gdb/gdb/testsuite/gdb.base/frame-view.c, line 42.
    (gdb) run
    Starting program: /home/simark/build/binutils-gdb/gdb/testsuite/outputs/gdb.base/frame-view/frame-view

    [Thread debugging using libthread_db enabled]
    Using host libthread_db library "/usr/lib/../lib/libthread_db.so.1".
    [New Thread 0x7ffff7cc46c0 (LWP 4171134)]
    [Switching to Thread 0x7ffff7cc46c0 (LWP 4171134)]

    Thread 2 "frame-view" hit Breakpoint 1, thread_func (p=0x0) at /home/simark/src/binutils-gdb/gdb/testsuite/gdb.base/frame-view.c:42
    42        foo (11);
    (gdb) info frame
    Stack level 0, frame at 0x7ffff7cc3ee0:
     rip = 0x5555555551a2 in thread_func (/home/simark/src/binutils-gdb/gdb/testsuite/gdb.base/frame-view.c:42); saved rip = 0x7ffff7d4e8fd
     called by frame at 0x7ffff7cc3f80
     source language c.
     Arglist at 0x7ffff7cc3ed0, args: p=0x0
     Locals at 0x7ffff7cc3ed0, Previous frame's sp is 0x7ffff7cc3ee0
     Saved registers:
      rbp at 0x7ffff7cc3ed0, rip at 0x7ffff7cc3ed8
    (gdb) thread 1
    [Switching to thread 1 (Thread 0x7ffff7cc5740 (LWP 4171122))]
    #0  0x00007ffff7d4b4b6 in ?? () from /usr/lib/libc.so.6

Here, we create a custom frame for thread 1 (using the stack from thread
2, for convenience):

    (gdb) select-frame view 0x7ffff7cc3f80 0x5555555551a2

The first calls to "frame" looks good:

    (gdb) frame
    #0  thread_func (p=0x7ffff7d4e630) at /home/simark/src/binutils-gdb/gdb/testsuite/gdb.base/frame-view.c:42
    42        foo (11);

But not the second one:

    (gdb) frame
    #0  0x00007ffff7d4b4b6 in ?? () from /usr/lib/libc.so.6

This second "frame" command shows the current target frame instead of
the user-created frame.

It's not totally clear how the "select-frame view" feature is expected
to behave, especially since it's not tested.  I heard accounts that it
used to be possible to select a frame like this and do "up" and "down"
to navigate the backtrace starting from that frame.  The fact that
create_new_frame calls frame_unwind_find_by_frame to install the right
unwinder suggest that it used to be possible.  But that doesn't work
today:

    (gdb) select-frame view 0x7ffff7cc3f80 0x5555555551a2
    (gdb) up
    Initial frame selected; you cannot go up.
    (gdb) down
    Bottom (innermost) frame selected; you cannot go down.

and "backtrace" always shows the actual thread's backtrace, it ignores
the user-created frame:

    (gdb) bt
    #0  0x00007ffff7d4b4b6 in ?? () from /usr/lib/libc.so.6
    #1  0x00007ffff7d50403 in ?? () from /usr/lib/libc.so.6
    bminor#2  0x000055555555521a in main () at /home/simark/src/binutils-gdb/gdb/testsuite/gdb.base/frame-view.c:56

I don't want to address all the `select-frame view` issues , but I think
we can agree that the "frame" command changing the selected frame, as
shown above, is a bug.  I would expect that command to show the
currently selected frame and not change it.

This happens because of the scoped_restore_selected_frame object in
print_frame_args.  The frame information is saved in the constructor
(the backtrace below), and restored in the destructor.

    #0  save_selected_frame (frame_id=0x7ffdc0020ad0, frame_level=0x7ffdc0020af0) at /home/simark/src/binutils-gdb/gdb/frame.c:1682
    #1  0x00005631390242f0 in scoped_restore_selected_frame::scoped_restore_selected_frame (this=0x7ffdc0020ad0) at /home/simark/src/binutils-gdb/gdb/frame.c:324
    bminor#2  0x000056313993581e in print_frame_args (fp_opts=..., func=0x62100023bde0, frame=..., num=-1, stream=0x60b000000300) at /home/simark/src/binutils-gdb/gdb/stack.c:755
    bminor#3  0x000056313993ad49 in print_frame (fp_opts=..., frame=..., print_level=1, print_what=SRC_AND_LOC, print_args=1, sal=...) at /home/simark/src/binutils-gdb/gdb/stack.c:1401
    bminor#4  0x000056313993835d in print_frame_info (fp_opts=..., frame=..., print_level=1, print_what=SRC_AND_LOC, print_args=1, set_current_sal=1) at /home/simark/src/binutils-gdb/gdb/stack.c:1126
    bminor#5  0x0000563139932e0b in print_stack_frame (frame=..., print_level=1, print_what=SRC_AND_LOC, set_current_sal=1) at /home/simark/src/binutils-gdb/gdb/stack.c:368
    bminor#6  0x0000563139932bbe in print_stack_frame_to_uiout (uiout=0x611000016840, frame=..., print_level=1, print_what=SRC_AND_LOC, set_current_sal=1) at /home/simark/src/binutils-gdb/gdb/stack.c:346
    bminor#7  0x0000563139b0641e in print_selected_thread_frame (uiout=0x611000016840, selection=...) at /home/simark/src/binutils-gdb/gdb/thread.c:1993
    bminor#8  0x0000563139940b7f in frame_command_core (fi=..., ignored=true) at /home/simark/src/binutils-gdb/gdb/stack.c:1871
    bminor#9  0x000056313994db9e in frame_command_helper<frame_command_core>::base_command (arg=0x0, from_tty=1) at /home/simark/src/binutils-gdb/gdb/stack.c:1976

Since the user-created frame has level 0 (identified by the saved level
-1), lookup_selected_frame just reselects the target's current frame,
and the user-created frame is lost.

My goal here is to fix this particular problem.

Currently, select_frame does not set selected_frame_id and
selected_frame_level for frames with level 0.  It leaves them at
null_frame_id / -1, indicating to restore_selected_frame to use the
target's current frame.  User-created frames also have level 0, so add a
special case them such that select_frame saves their selected id and
level.

save_selected_frame does not need any change.

Change the assertion in restore_selected_frame that checks `frame_level
!= 0` to account for the fact that we can restore user-created frames,
which have level 0.

Finally, change lookup_selected_frame to make it able to re-create
user-created frame_info objects from selected_frame_level and
selected_frame_id.

Add a minimal test case for the case described above, that is the
"select-frame view" command followed by the "frame" command twice.  In
order to have a known stack frame to switch to, the test spawns a second
thread, and tells the first thread to use the other thread's top frame.

Change-Id: Ifc77848dc465fbd21324b9d44670833e09fe98c7
Reviewed-By: Bruno Larsen <blarsen@redhat.com>
@ecatmur ecatmur force-pushed the bug-17272 branch 3 times, most recently from 7df1856 to 4e3e29a Compare February 4, 2023 16:16
This patch adds support for DW_TAG_GNU_formal_parameter_pack and
DW_TAG_GNU_template_parameter_pack, added to DWARF in March 2009 for
C++11 variadic templates[1].

They are not currently emitted thanks to a typo[2] but the fix is
trivial[3] and has been repeatedly submitted[4] to gcc; I'm not sure
what else I can do to get it accepted; regardless, anyone building their
own compiler can still make use of this.

This implementation synthesizes type and parameter names as T#n, p#n
e.g. Args#1, args#1. This is a pretty simple approach but it seems to
work OK and is compatible with the old style type and parameter names
emitted by old versions of gcc and when it's writing stabs+ format,
meaning that any debugger scripts will continue to work.

1. http://wiki.dwarfstd.org/index.php?title=C%2B%2B0x:_Variadic_templates
2. https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70536
3. ecatmur/gcc#5
4. https://gcc.gnu.org/pipermail/gcc-patches/2023-January/609659.html
PR. https://sourceware.org/bugzilla/show_bug.cgi?id=17272
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ecatmur commented Feb 4, 2023

Resent just now (no changes, just a better description): https://sourceware.org/pipermail/gdb-patches/2023-February/196618.html

ecatmur pushed a commit that referenced this pull request May 17, 2023
In some cases GDB will fail when attempting to complete a command that
involves a rust symbol, the failure can manifest as a crash.

The problem is caused by the completion_match_for_lcd object being
left containing invalid data during calls to cp_symbol_name_matches_1.

The first question to address is why we are calling a C++ support
function when handling a rust symbol.  That's due to GDB's auto
language detection for msymbols, in some cases GDB can't tell if a
symbol is a rust symbol, or a C++ symbol.

The test application contains symbols for functions which are
statically linked in from various rust support libraries.  There's no
DWARF for these symbols, so all GDB has is the msymbols built from the
ELF symbol table.

Here's the problematic symbol that leads to our crash:

    mangled: _ZN4core3str21_$LT$impl$u20$str$GT$5parse17h5111d2d6a50d22bdE
  demangled: core::str::<impl str>::parse

As an msymbol this is initially created with language auto, then GDB
eventually calls symbol_find_demangled_name, which loops over all
languages calling language_defn::sniff_from_mangled_name, the first
language that can demangle the symbol gets assigned as the language
for that symbol.

Unfortunately, there's overlap in the mangled symbol names,
some (legacy) rust symbols can be demangled as both rust and C++, see
cplus_demangle in libiberty/cplus-dem.c where this is mentioned.

And so, because we check the C++ language before we check for rust,
then the msymbol is (incorrectly) given the C++ language.

Now it's true that is some cases we might be able to figure out that a
demangled symbol is not actually a valid C++ symbol, for example, in
our case, the construct '::<impl str>::' is not, I believe, valid in a
C++ symbol, we could look for ':<' and '>:' and refuse to accept this
as a C++ symbol.

However, I'm not sure it is always possible to tell that a demangled
symbol is rust or C++, so, I think, we have to accept that some times
we will get this language detection wrong.

If we accept that we can't fix the symbol language detection 100% of
the time, then we should make sure that GDB doesn't crash when it gets
the language wrong, that is what this commit addresses.

In our test case the user tries to complete a symbol name like this:

  (gdb) complete break pars

This results in GDB trying to find all symbols that match 'pars',
eventually we consider our problematic symbol, and we end up with a
call stack that looks like this:

  #0  0x0000000000f3c6bd in strncmp_iw_with_mode
  #1  0x0000000000706d8d in cp_symbol_name_matches_1
  bminor#2  0x0000000000706fa4 in cp_symbol_name_matches
  bminor#3  0x0000000000df3c45 in compare_symbol_name
  bminor#4  0x0000000000df3c91 in completion_list_add_name
  bminor#5  0x0000000000df3f1d in completion_list_add_msymbol
  bminor#6  0x0000000000df4c94 in default_collect_symbol_completion_matches_break_on
  bminor#7  0x0000000000658c08 in language_defn::collect_symbol_completion_matches
  bminor#8  0x0000000000df54c9 in collect_symbol_completion_matches
  bminor#9  0x00000000009d98fb in linespec_complete_function
  bminor#10 0x00000000009d99f0 in complete_linespec_component
  bminor#11 0x00000000009da200 in linespec_complete
  bminor#12 0x00000000006e4132 in complete_address_and_linespec_locations
  bminor#13 0x00000000006e4ac3 in location_completer

In cp_symbol_name_matches_1 we enter a loop, this loop repeatedly
tries to match the demangled problematic symbol name against the user
supplied text ('pars').  Each time around the loop another component
of the symbol name is stripped off, thus, we check 'pars' against
these options:

  core::str::<impl str>::parse
  str::<impl str>::parse
  <impl str>::parse
  parse

As soon as we get a match the cp_symbol_name_matches_1 exits its loop
and returns.  In our case, when we're looking for 'pars', the match
occurs on the last iteration of the loop, when we are comparing to
'parse'.

Now the problem here is that cp_symbol_name_matches_1 uses the
strncmp_iw_with_mode, and inside strncmp_iw_with_mode we allow for
skipping over template parameters.  This allows GDB to match the
symbol name 'foo<int>(int,int)' if the user supplies 'foo(int,'.
Inside strncmp_iw_with_mode GDB will record any template arguments
that it has skipped over inside the completion_match_for_lcd object
that is passed in as an argument.

And so, when GDB tries to match against '<impl str>::parse', the first
thing it sees is '<impl str>', GDB assumes this is a template argument
and records this as a skipped region within the
completion_match_for_lcd object.  After '<impl str>' GDB sees a ':'
character, which doesn't match with the 'pars' the user supplied, so
strncmp_iw_with_mode returns a value indicating a non-match.  GDB then
removes the '<impl str>' component from the symbol name and tries
again, this time comparing to 'parse', which does match.

Having found a match, then in cp_symbol_name_matches_1 we record the
match string, and the full symbol name within the
completion_match_result object, and return.

The problem here is that the skipped region, the '<impl str>' that we
recorded in the penultimate loop iteration was never discarded, its
still there in our returned result.

If we look at what the pointers held in the completion_match_result
that cp_symbol_name_matches_1 returns, this is what we see:

  core::str::<impl str>::parse
  |          \________/  |
  |               |      '--- completion match string
  |               '---skip range
  '--- full symbol name

When GDB calls completion_match_for_lcd::finish, GDB tries to create a
string using the completion match string (parse), but excluding the
skip range, as the stored skip range is before the start of the
completion match string, then GDB tries to do some weird string
creation, which will cause GDB to crash.

The reason we don't often see this problem in C++ is that for C++
symbols there is always some non-template text before the template
argument.  This non-template text means GDB is likely to either match
the symbol, or reject the symbol without storing a skip range.

However, notice, I did say, we don't often see this problem.  Once I
understood the issue, I was able to reproduce the crash using a pure
C++ example:

  template<typename S>
  struct foo
  {
    template<typename T>
    foo (int p1, T a)
    {
      s = 0;
    }

    S s;
  };

  int
  main ()
  {
    foo<int> obj (2.3, 0);
    return 0;
  }

Then in GDB:

  (gdb) complete break foo(int

The problem here is that the C++ symbol for the constructor looks like
this:

  foo<int>::foo<double>(int, double)

When GDB enters cp_symbol_name_matches_1 the symbols it examines are:

  foo<int>::foo<double>(int, double)
  foo<double>(int, double)

The first iteration of the loop will match the 'foo', then add the
'<int>' template argument will be added as a skip range.  When GDB
find the ':' after the '<int>' the first iteration of the loop fails
to match, GDB removes the 'foo<int>::' component, and starts the
second iteration of the loop.

Again, GDB matches the 'foo', and now adds '<double>' as a skip
region.  After that the '(int' successfully matches, and so the second
iteration of the loop succeeds, but, once again we left the '<int>' in
place as a skip region, even though this occurs before the start of
our match string, and this will cause GDB to crash.

This problem was reported to the mailing list, and a solution
discussed in this thread:

  https://sourceware.org/pipermail/gdb-patches/2023-January/195166.html

The solution proposed here is similar to one proposed by the original
bug reported, but implemented in a different location within GDB.
Instead of placing the fix in strncmp_iw_with_mode, I place the fix in
cp_symbol_name_matches_1.  I believe this is a better location as it
is this function that implements the loop, and it is this loop, which
repeatedly calls strncmp_iw_with_mode, that should be resetting the
result object state (I believe).

What I have done is add an assert to strncmp_iw_with_mode that the
incoming result object is empty.

I've also added some other asserts in related code, in
completion_match_for_lcd::mark_ignored_range, I make some basic
assertions about the incoming range pointers, and in
completion_match_for_lcd::finish I also make some assertions about how
the skip ranges relate to the match pointer.

There's two new tests.  The original rust example that was used in the
initial bug report, and a C++ test.  The rust example depends on which
symbols are pulled in from the rust libraries, so it is possible that,
at some future date, the problematic symbol will disappear from this
test program.  The C++ test should be more reliable, as this only
depends on symbols from within the C++ source code.

Since I originally posted this patch to the mailing list, the
following patch has been merged:

  commit 6e7eef7
  Date:   Sun Mar 19 09:13:10 2023 -0600

      Use rust_demangle to fix a crash

This solves the problem of a rust symbol ending up in the C++ specific
code by changing the order languages are sorted.  However, this new
commit doesn't address the issue in the C++ code which was fixed with
this commit.

Given that the C++ issue is real, and has a reproducer, I'm still
going to merge this fix.  I've left the discussion of rust in this
commit message as I originally wrote it, but it should be read within
the context of GDB prior to commit 6e7eef7.

Co-Authored-By:  Zheng Zhan <zzlossdev@163.com>
ecatmur pushed a commit that referenced this pull request May 17, 2023
In the case where a Fortran program has a program name of "main" and
there is also a minimal symbol called main, such as with programs built
with GCC version 4.4.7 or below, the backtrace will erroneously stop at
the minimal symbol rather than the user specified main, e.g.:

(gdb) bt
#0  bar () at .../gdb/testsuite/gdb.fortran/backtrace.f90:17
#1  0x0000000000402556 in foo () at .../gdb/testsuite/gdb.fortran/backtrace.f90:21
bminor#2  0x0000000000402575 in main () at .../gdb/testsuite/gdb.fortran/backtrace.f90:31
bminor#3  0x00000000004025aa in main ()
(gdb)

This patch fixes this issue by increasing the precedence of the full
symbol when the language of the current frame is Fortran.

Newer versions of GCC transform the program name to "MAIN__" in this
case, avoiding the problem.

Co-Authored-By: Maciej W. Rozycki <macro@embecosm.com>
ecatmur pushed a commit that referenced this pull request May 17, 2023
GDB expected PC should point right after the SVC instruction when the
syscall is active. But some active syscalls keep PC pointing to the SVC
instruction itself.

This leads to a broken backtrace like:
 Backtrace stopped: previous frame identical to this frame (corrupt stack?)
 #0  0xb6f8681c in pthread_cond_timedwait@@GLIBC_2.4 () from /lib/arm-linux-gnueabihf/libpthread.so.0
 #1  0xb6e21f80 in ?? ()

The reason is that .ARM.exidx unwinder gives up if PC does not point
right after the SVC (syscall) instruction. I did not investigate why but
some syscalls will point PC to the SVC instruction itself. This happens
for the "futex" syscall used by pthread_cond_timedwait.

That normally does not matter as ARM prologue unwinder gets called
instead of the .ARM.exidx one. Unfortunately some glibc calls have more
complicated prologue where the GDB unwinder fails to properly determine
the return address (that is in fact an orthogonal GDB bug). I expect it
is due to the "vpush" there in this case but I did not investigate it more:

Dump of assembler code for function pthread_cond_timedwait@@GLIBC_2.4:
   0xb6f8757c <+0>:     push    {r4, r5, r6, r7, r8, r9, r10, r11, lr}
   0xb6f87580 <+4>:     mov     r10, r2
   0xb6f87584 <+8>:     vpush   {d8}

Regression tested on armv7l kernel 5.15.32-v7l+ (Raspbian 11).

Approved-By: Luis Machado <luis.machado@arm.com>
ecatmur pushed a commit that referenced this pull request May 17, 2023
When GDB fails to test the condition of a conditional breakpoint, for
whatever reason, the error message looks like this:

  (gdb) break foo if (*(int *) 0) == 1
  Breakpoint 1 at 0x40111e: file bpcond.c, line 11.
  (gdb) r
  Starting program: /tmp/bpcond
  Error in testing breakpoint condition:
  Cannot access memory at address 0x0

  Breakpoint 1, foo () at bpcond.c:11
  11	  int a = 32;
  (gdb)

The line I'm interested in for this commit is this one:

  Error in testing breakpoint condition:

In the case above we can figure out that the problematic breakpoint
was #1 because in the final line of the message GDB reports the stop
at breakpoint #1.

However, in the next few patches I plan to change this.  In some cases
I don't think it makes sense for GDB to report the stop as being at
breakpoint #1, consider this case:

  (gdb) list some_func
  1	int
  2	some_func ()
  3	{
  4	  int *p = 0;
  5	  return *p;
  6	}
  7
  8	void
  9	foo ()
  10	{
  (gdb) break foo if (some_func ())
  Breakpoint 1 at 0x40111e: file bpcond.c, line 11.
  (gdb) r
  Starting program: /tmp/bpcond

  Program received signal SIGSEGV, Segmentation fault.
  0x0000000000401116 in some_func () at bpcond.c:5
  5	  return *p;
  Error in testing breakpoint condition:
  The program being debugged was signaled while in a function called from GDB.
  GDB remains in the frame where the signal was received.
  To change this behavior use "set unwindonsignal on".
  Evaluation of the expression containing the function
  (some_func) will be abandoned.
  When the function is done executing, GDB will silently stop.

  Program received signal SIGSEGV, Segmentation fault.

  Breakpoint 1, 0x0000000000401116 in some_func () at bpcond.c:5
  5	  return *p;
  (gdb)

Notice that, the final lines of output reports the stop as being at
breakpoint #1, even though the inferior in not located within
some_func, and it's certainly not located at the breakpoint location.

I find this behaviour confusing, and propose that this should be
changed.  However, if I make that change then every reference to
breakpoint #1 will be lost from the error message.

So, in this commit, in preparation for the later commits, I propose to
change the 'Error in testing breakpoint condition:' line to this:

  Error in testing condition for breakpoint NUMBER:

where NUMBER will be filled in as appropriate.  Here's the first
example with the updated error:

  (gdb) break foo if (*(int *) 0) == 0
  Breakpoint 1 at 0x40111e: file bpcond.c, line 11.
  (gdb) r
  Starting program: /tmp/bpcond
  Error in testing condition for breakpoint 1:
  Cannot access memory at address 0x0

  Breakpoint 1, foo () at bpcond.c:11
  11	  int a = 32;
  (gdb)

The breakpoint number does now appear twice in the output, but I don't
see that as a negative.

This commit just changes the one line of the error, and updates the
few tests that either included the old error in comments, or actually
checked for the error in the expected output.

As the only test that checked the line I modified is a Python test,
I've added a new test that doesn't rely on Python that checks the
error message in detail.

While working on the new test, I spotted that it would fail when run
with native-gdbserver and native-extended-gdbserver target boards.
This turns out to be due to a gdbserver bug.  To avoid cluttering this
commit I've added a work around to the new test script so that the
test passes for the remote boards, in the next few commits I will fix
gdbserver, and update the test script to remove the work around.
ecatmur pushed a commit that referenced this pull request May 17, 2023
Commit 7a8de0c ("Remove ALL_BREAKPOINTS_SAFE") introduced a
use-after-free in the breakpoints iterations (see below for full ASan
report).  This makes gdb.base/stale-infcall.exp fail when GDB is build
with ASan.

check_longjmp_breakpoint_for_call_dummy iterates on all breakpoints,
possibly deleting the current breakpoint as well as related breakpoints.
The problem arises when a breakpoint in the B->related_breakpoint chain
is also B->next.  In that case, deleting that related breakpoint frees
the breakpoint that all_breakpoints_safe has saved.

The old code worked around that by manually changing B_TMP, which was
the next breakpoint saved by the "safe iterator":

	while (b->related_breakpoint != b)
	  {
	    if (b_tmp == b->related_breakpoint)
	      b_tmp = b->related_breakpoint->next;
	    delete_breakpoint (b->related_breakpoint);
	  }

(Note that this seemed to assume that b->related_breakpoint->next was
the same as b->next->next, not sure this is guaranteed.)

The new code kept the B_TMP variable, but it's not useful in that
context.  We can't go change the next breakpoint as saved by the safe
iterator, like we did before.  I suggest fixing that by saving the
breakpoints to delete in a map and deleting them all at the end.

Here's the full ASan report:

    (gdb) PASS: gdb.base/stale-infcall.exp: continue to breakpoint: break-run1
    print infcall ()
    =================================================================
    ==47472==ERROR: AddressSanitizer: heap-use-after-free on address 0x611000034980 at pc 0x563f7012c7bc bp 0x7ffdf3804d70 sp 0x7ffdf3804d60
    READ of size 8 at 0x611000034980 thread T0
        #0 0x563f7012c7bb in next_iterator<breakpoint>::operator++() /home/smarchi/src/binutils-gdb/gdb/../gdbsupport/next-iterator.h:66
        #1 0x563f702ce8c0 in basic_safe_iterator<next_iterator<breakpoint> >::operator++() /home/smarchi/src/binutils-gdb/gdb/../gdbsupport/safe-iterator.h:84
        bminor#2 0x563f7021522a in check_longjmp_breakpoint_for_call_dummy(thread_info*) /home/smarchi/src/binutils-gdb/gdb/breakpoint.c:7611
        bminor#3 0x563f714567b1 in process_event_stop_test /home/smarchi/src/binutils-gdb/gdb/infrun.c:6881
        bminor#4 0x563f71454e07 in handle_signal_stop /home/smarchi/src/binutils-gdb/gdb/infrun.c:6769
        bminor#5 0x563f7144b680 in handle_inferior_event /home/smarchi/src/binutils-gdb/gdb/infrun.c:6023
        bminor#6 0x563f71436165 in fetch_inferior_event() /home/smarchi/src/binutils-gdb/gdb/infrun.c:4387
        bminor#7 0x563f7136ff51 in inferior_event_handler(inferior_event_type) /home/smarchi/src/binutils-gdb/gdb/inf-loop.c:42
        bminor#8 0x563f7168038d in handle_target_event /home/smarchi/src/binutils-gdb/gdb/linux-nat.c:4219
        bminor#9 0x563f72fccb6d in handle_file_event /home/smarchi/src/binutils-gdb/gdbsupport/event-loop.cc:573
        bminor#10 0x563f72fcd503 in gdb_wait_for_event /home/smarchi/src/binutils-gdb/gdbsupport/event-loop.cc:694
        bminor#11 0x563f72fcaf2b in gdb_do_one_event(int) /home/smarchi/src/binutils-gdb/gdbsupport/event-loop.cc:217
        bminor#12 0x563f7262b9bb in wait_sync_command_done() /home/smarchi/src/binutils-gdb/gdb/top.c:426
        bminor#13 0x563f7137a7c3 in run_inferior_call /home/smarchi/src/binutils-gdb/gdb/infcall.c:650
        bminor#14 0x563f71381295 in call_function_by_hand_dummy(value*, type*, gdb::array_view<value*>, void (*)(void*, int), void*) /home/smarchi/src/binutils-gdb/gdb/infcall.c:1332
        bminor#15 0x563f7137c0e2 in call_function_by_hand(value*, type*, gdb::array_view<value*>) /home/smarchi/src/binutils-gdb/gdb/infcall.c:780
        bminor#16 0x563f70fe5960 in evaluate_subexp_do_call(expression*, noside, value*, gdb::array_view<value*>, char const*, type*) /home/smarchi/src/binutils-gdb/gdb/eval.c:649
        bminor#17 0x563f70fe6617 in expr::operation::evaluate_funcall(type*, expression*, noside, char const*, std::__debug::vector<std::unique_ptr<expr::operation, std::default_delete<expr::operation> >, std::allocator<std::unique_ptr<expr::operation, std::default_delete<expr::operation> > > > const&) /home/smarchi/src/binutils-gdb/gdb/eval.c:677
        #18 0x563f6fd19668 in expr::operation::evaluate_funcall(type*, expression*, noside, std::__debug::vector<std::unique_ptr<expr::operation, std::default_delete<expr::operation> >, std::allocator<std::unique_ptr<expr::operation, std::default_delete<expr::operation> > > > const&) /home/smarchi/src/binutils-gdb/gdb/expression.h:136
        #19 0x563f70fe6bba in expr::var_value_operation::evaluate_funcall(type*, expression*, noside, std::__debug::vector<std::unique_ptr<expr::operation, std::default_delete<expr::operation> >, std::allocator<std::unique_ptr<expr::operation, std::default_delete<expr::operation> > > > const&) /home/smarchi/src/binutils-gdb/gdb/eval.c:689
        #20 0x563f704b71dc in expr::funcall_operation::evaluate(type*, expression*, noside) /home/smarchi/src/binutils-gdb/gdb/expop.h:2219
        #21 0x563f70fe0f02 in expression::evaluate(type*, noside) /home/smarchi/src/binutils-gdb/gdb/eval.c:110
        #22 0x563f71b1373e in process_print_command_args /home/smarchi/src/binutils-gdb/gdb/printcmd.c:1319
        #23 0x563f71b1391b in print_command_1 /home/smarchi/src/binutils-gdb/gdb/printcmd.c:1332
        #24 0x563f71b147ec in print_command /home/smarchi/src/binutils-gdb/gdb/printcmd.c:1465
        #25 0x563f706029b8 in do_simple_func /home/smarchi/src/binutils-gdb/gdb/cli/cli-decode.c:95
        #26 0x563f7061972a in cmd_func(cmd_list_element*, char const*, int) /home/smarchi/src/binutils-gdb/gdb/cli/cli-decode.c:2735
        #27 0x563f7262d0ef in execute_command(char const*, int) /home/smarchi/src/binutils-gdb/gdb/top.c:572
        #28 0x563f7100ed9c in command_handler(char const*) /home/smarchi/src/binutils-gdb/gdb/event-top.c:543
        #29 0x563f7101014b in command_line_handler(std::unique_ptr<char, gdb::xfree_deleter<char> >&&) /home/smarchi/src/binutils-gdb/gdb/event-top.c:779
        #30 0x563f72777942 in tui_command_line_handler /home/smarchi/src/binutils-gdb/gdb/tui/tui-interp.c:104
        #31 0x563f7100d059 in gdb_rl_callback_handler /home/smarchi/src/binutils-gdb/gdb/event-top.c:250
        #32 0x7f5a80418246 in rl_callback_read_char (/usr/lib/libreadline.so.8+0x3b246) (BuildId: 092e91fc4361b0ef94561e3ae03a75f69398acbb)
        #33 0x563f7100ca06 in gdb_rl_callback_read_char_wrapper_noexcept /home/smarchi/src/binutils-gdb/gdb/event-top.c:192
        #34 0x563f7100cc5e in gdb_rl_callback_read_char_wrapper /home/smarchi/src/binutils-gdb/gdb/event-top.c:225
        #35 0x563f728c70db in stdin_event_handler /home/smarchi/src/binutils-gdb/gdb/ui.c:155
        #36 0x563f72fccb6d in handle_file_event /home/smarchi/src/binutils-gdb/gdbsupport/event-loop.cc:573
        #37 0x563f72fcd503 in gdb_wait_for_event /home/smarchi/src/binutils-gdb/gdbsupport/event-loop.cc:694
        #38 0x563f72fcb15c in gdb_do_one_event(int) /home/smarchi/src/binutils-gdb/gdbsupport/event-loop.cc:264
        #39 0x563f7177ec1c in start_event_loop /home/smarchi/src/binutils-gdb/gdb/main.c:412
        #40 0x563f7177f12e in captured_command_loop /home/smarchi/src/binutils-gdb/gdb/main.c:476
        #41 0x563f717846e4 in captured_main /home/smarchi/src/binutils-gdb/gdb/main.c:1320
        #42 0x563f71784821 in gdb_main(captured_main_args*) /home/smarchi/src/binutils-gdb/gdb/main.c:1339
        #43 0x563f6fcedfbd in main /home/smarchi/src/binutils-gdb/gdb/gdb.c:32
        #44 0x7f5a7e43984f  (/usr/lib/libc.so.6+0x2384f) (BuildId: 2f005a79cd1a8e385972f5a102f16adba414d75e)
        #45 0x7f5a7e439909 in __libc_start_main (/usr/lib/libc.so.6+0x23909) (BuildId: 2f005a79cd1a8e385972f5a102f16adba414d75e)
        #46 0x563f6fcedd84 in _start (/home/smarchi/build/binutils-gdb/gdb/gdb+0xafb0d84) (BuildId: 50bd32e6e9d5e84543e9897b8faca34858ca3995)

    0x611000034980 is located 0 bytes inside of 208-byte region [0x611000034980,0x611000034a50)
    freed by thread T0 here:
        #0 0x7f5a7fce312a in operator delete(void*, unsigned long) /usr/src/debug/gcc/gcc/libsanitizer/asan/asan_new_delete.cpp:164
        #1 0x563f702bd1fa in momentary_breakpoint::~momentary_breakpoint() /home/smarchi/src/binutils-gdb/gdb/breakpoint.c:304
        bminor#2 0x563f702771c5 in delete_breakpoint(breakpoint*) /home/smarchi/src/binutils-gdb/gdb/breakpoint.c:12404
        bminor#3 0x563f702150a7 in check_longjmp_breakpoint_for_call_dummy(thread_info*) /home/smarchi/src/binutils-gdb/gdb/breakpoint.c:7673
        bminor#4 0x563f714567b1 in process_event_stop_test /home/smarchi/src/binutils-gdb/gdb/infrun.c:6881
        bminor#5 0x563f71454e07 in handle_signal_stop /home/smarchi/src/binutils-gdb/gdb/infrun.c:6769
        bminor#6 0x563f7144b680 in handle_inferior_event /home/smarchi/src/binutils-gdb/gdb/infrun.c:6023
        bminor#7 0x563f71436165 in fetch_inferior_event() /home/smarchi/src/binutils-gdb/gdb/infrun.c:4387
        bminor#8 0x563f7136ff51 in inferior_event_handler(inferior_event_type) /home/smarchi/src/binutils-gdb/gdb/inf-loop.c:42
        bminor#9 0x563f7168038d in handle_target_event /home/smarchi/src/binutils-gdb/gdb/linux-nat.c:4219
        bminor#10 0x563f72fccb6d in handle_file_event /home/smarchi/src/binutils-gdb/gdbsupport/event-loop.cc:573
        bminor#11 0x563f72fcd503 in gdb_wait_for_event /home/smarchi/src/binutils-gdb/gdbsupport/event-loop.cc:694
        bminor#12 0x563f72fcaf2b in gdb_do_one_event(int) /home/smarchi/src/binutils-gdb/gdbsupport/event-loop.cc:217
        bminor#13 0x563f7262b9bb in wait_sync_command_done() /home/smarchi/src/binutils-gdb/gdb/top.c:426
        bminor#14 0x563f7137a7c3 in run_inferior_call /home/smarchi/src/binutils-gdb/gdb/infcall.c:650
        bminor#15 0x563f71381295 in call_function_by_hand_dummy(value*, type*, gdb::array_view<value*>, void (*)(void*, int), void*) /home/smarchi/src/binutils-gdb/gdb/infcall.c:1332
        bminor#16 0x563f7137c0e2 in call_function_by_hand(value*, type*, gdb::array_view<value*>) /home/smarchi/src/binutils-gdb/gdb/infcall.c:780
        bminor#17 0x563f70fe5960 in evaluate_subexp_do_call(expression*, noside, value*, gdb::array_view<value*>, char const*, type*) /home/smarchi/src/binutils-gdb/gdb/eval.c:649
        #18 0x563f70fe6617 in expr::operation::evaluate_funcall(type*, expression*, noside, char const*, std::__debug::vector<std::unique_ptr<expr::operation, std::default_delete<expr::operation> >, std::allocator<std::unique_ptr<expr::operation, std::default_delete<expr::operation> > > > const&) /home/smarchi/src/binutils-gdb/gdb/eval.c:677
        #19 0x563f6fd19668 in expr::operation::evaluate_funcall(type*, expression*, noside, std::__debug::vector<std::unique_ptr<expr::operation, std::default_delete<expr::operation> >, std::allocator<std::unique_ptr<expr::operation, std::default_delete<expr::operation> > > > const&) /home/smarchi/src/binutils-gdb/gdb/expression.h:136
        #20 0x563f70fe6bba in expr::var_value_operation::evaluate_funcall(type*, expression*, noside, std::__debug::vector<std::unique_ptr<expr::operation, std::default_delete<expr::operation> >, std::allocator<std::unique_ptr<expr::operation, std::default_delete<expr::operation> > > > const&) /home/smarchi/src/binutils-gdb/gdb/eval.c:689
        #21 0x563f704b71dc in expr::funcall_operation::evaluate(type*, expression*, noside) /home/smarchi/src/binutils-gdb/gdb/expop.h:2219
        #22 0x563f70fe0f02 in expression::evaluate(type*, noside) /home/smarchi/src/binutils-gdb/gdb/eval.c:110
        #23 0x563f71b1373e in process_print_command_args /home/smarchi/src/binutils-gdb/gdb/printcmd.c:1319
        #24 0x563f71b1391b in print_command_1 /home/smarchi/src/binutils-gdb/gdb/printcmd.c:1332
        #25 0x563f71b147ec in print_command /home/smarchi/src/binutils-gdb/gdb/printcmd.c:1465
        #26 0x563f706029b8 in do_simple_func /home/smarchi/src/binutils-gdb/gdb/cli/cli-decode.c:95
        #27 0x563f7061972a in cmd_func(cmd_list_element*, char const*, int) /home/smarchi/src/binutils-gdb/gdb/cli/cli-decode.c:2735
        #28 0x563f7262d0ef in execute_command(char const*, int) /home/smarchi/src/binutils-gdb/gdb/top.c:572
        #29 0x563f7100ed9c in command_handler(char const*) /home/smarchi/src/binutils-gdb/gdb/event-top.c:543

    previously allocated by thread T0 here:
        #0 0x7f5a7fce2012 in operator new(unsigned long) /usr/src/debug/gcc/gcc/libsanitizer/asan/asan_new_delete.cpp:95
        #1 0x563f7029a9a3 in new_momentary_breakpoint<program_space*&, frame_id&, int&> /home/smarchi/src/binutils-gdb/gdb/breakpoint.c:8129
        bminor#2 0x563f702212f6 in momentary_breakpoint_from_master /home/smarchi/src/binutils-gdb/gdb/breakpoint.c:8169
        bminor#3 0x563f70212db1 in set_longjmp_breakpoint_for_call_dummy() /home/smarchi/src/binutils-gdb/gdb/breakpoint.c:7582
        bminor#4 0x563f713804db in call_function_by_hand_dummy(value*, type*, gdb::array_view<value*>, void (*)(void*, int), void*) /home/smarchi/src/binutils-gdb/gdb/infcall.c:1260
        bminor#5 0x563f7137c0e2 in call_function_by_hand(value*, type*, gdb::array_view<value*>) /home/smarchi/src/binutils-gdb/gdb/infcall.c:780
        bminor#6 0x563f70fe5960 in evaluate_subexp_do_call(expression*, noside, value*, gdb::array_view<value*>, char const*, type*) /home/smarchi/src/binutils-gdb/gdb/eval.c:649
        bminor#7 0x563f70fe6617 in expr::operation::evaluate_funcall(type*, expression*, noside, char const*, std::__debug::vector<std::unique_ptr<expr::operation, std::default_delete<expr::operation> >, std::allocator<std::unique_ptr<expr::operation, std::default_delete<expr::operation> > > > const&) /home/smarchi/src/binutils-gdb/gdb/eval.c:677
        bminor#8 0x563f6fd19668 in expr::operation::evaluate_funcall(type*, expression*, noside, std::__debug::vector<std::unique_ptr<expr::operation, std::default_delete<expr::operation> >, std::allocator<std::unique_ptr<expr::operation, std::default_delete<expr::operation> > > > const&) /home/smarchi/src/binutils-gdb/gdb/expression.h:136
        bminor#9 0x563f70fe6bba in expr::var_value_operation::evaluate_funcall(type*, expression*, noside, std::__debug::vector<std::unique_ptr<expr::operation, std::default_delete<expr::operation> >, std::allocator<std::unique_ptr<expr::operation, std::default_delete<expr::operation> > > > const&) /home/smarchi/src/binutils-gdb/gdb/eval.c:689
        bminor#10 0x563f704b71dc in expr::funcall_operation::evaluate(type*, expression*, noside) /home/smarchi/src/binutils-gdb/gdb/expop.h:2219
        bminor#11 0x563f70fe0f02 in expression::evaluate(type*, noside) /home/smarchi/src/binutils-gdb/gdb/eval.c:110
        bminor#12 0x563f71b1373e in process_print_command_args /home/smarchi/src/binutils-gdb/gdb/printcmd.c:1319
        bminor#13 0x563f71b1391b in print_command_1 /home/smarchi/src/binutils-gdb/gdb/printcmd.c:1332
        bminor#14 0x563f71b147ec in print_command /home/smarchi/src/binutils-gdb/gdb/printcmd.c:1465
        bminor#15 0x563f706029b8 in do_simple_func /home/smarchi/src/binutils-gdb/gdb/cli/cli-decode.c:95
        bminor#16 0x563f7061972a in cmd_func(cmd_list_element*, char const*, int) /home/smarchi/src/binutils-gdb/gdb/cli/cli-decode.c:2735
        bminor#17 0x563f7262d0ef in execute_command(char const*, int) /home/smarchi/src/binutils-gdb/gdb/top.c:572
        #18 0x563f7100ed9c in command_handler(char const*) /home/smarchi/src/binutils-gdb/gdb/event-top.c:543
        #19 0x563f7101014b in command_line_handler(std::unique_ptr<char, gdb::xfree_deleter<char> >&&) /home/smarchi/src/binutils-gdb/gdb/event-top.c:779
        #20 0x563f72777942 in tui_command_line_handler /home/smarchi/src/binutils-gdb/gdb/tui/tui-interp.c:104
        #21 0x563f7100d059 in gdb_rl_callback_handler /home/smarchi/src/binutils-gdb/gdb/event-top.c:250
        #22 0x7f5a80418246 in rl_callback_read_char (/usr/lib/libreadline.so.8+0x3b246) (BuildId: 092e91fc4361b0ef94561e3ae03a75f69398acbb)

Change-Id: Id00c17ab677f847fbf4efdf0f4038373668d3d88
Approved-By: Tom Tromey <tom@tromey.com>
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